Gaseous electric discharge device



Feb. 11, 1936.

E. G. DORG ELb ,030,433

GASEOUS ELECTRIC DISCHARGE DEVICE Filed April 6, 1934 INVENTOR Patented Feb. 11, 1936 PATENT OFFICE 2,030,433 GASEOUS ELECTRIC DISCHARGE DEVICE Eduard G. Dorgelo, Eindhoven, Netherlands, assignor to General Electric Company, a corporation of New York Application April 6, 1934', Serial No. 719,251

' In the Netherlands April 22, 1933 '4 Claims. :(c1.1'1c-1) The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices useful as light sources and as ultra-violet generators. I

The object of the invention is to provide a gaseous electric discharge device of simple structure useful as alight source and as an ultraviolet generator. Another object of the inven- 1 tion is to provide a gaseous electric discharge lamp the emitted light of whichis a mixture of light from an incandescent body and an electric discharge. A further object of the invention is to provide such a device the manufacturing cost 1.3 of which is reduced to a minimum. Still fu1ther objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description. In accordance with these objects the new novel gaseous electric discharge device comprises a container having a gaseous atmosphere therein. Said container has mounted therein two resistances connected in series and a thermionic, filamentary cathode provided with electron emitting -material, which cathode is connected in series with said resistances and mounted between said resistances. When the cathode is of the type having a heating element this ele- 30 ment is connected in series with said resistances. When the device is connected to a source of alternating current a potential diflerence is created between the cathode located in the center of this series connection and the ends of the resistances that are not connected to this cathode. Each of these ends has alternately, a positive and a negative potential with respect to the cathode. A discharge then takes place between the cathode and that end of the resist- 40' ance which, at that particular instant, has a positive potential with respect to the cathode, while the other resistance serves as a series impedance'for the discharge. In the subsequent half-cycle of the alternating current, the funcing elements, in which case a third resistance is connected-between these two glow electrodes or heating elements. As will be explained in greater detail later herein this third resistance coacts in the production of the voltage for the discharge but does not constitute a part of the series resistance which is connected in series with the discharge.

The resistances are preferably selected of such a size that they become incandescent during operation and emit light. These light rays then mix with the rays produced by the discharge. When the discharge device is used as an ultraviolet generator the container I is made of a material which transmits ultra-violet rays, such as quartz.

When desired, those ends of the resistances which function as anodes have'a special shape in order to make these ends better suited to carry the discharge current. The ends are made thicker or provided with a special small metal plate, for example.

The construction of the discharge device 30-.-

cording to the invention is very simple, especially because of the fact that only two current-supply discharge device embodying the present invention,

Fig. 2 is a wi ring diagram of another embodiment of the invention, and

Fig. 3 is a wiring diagram of another embodiment of the invention.

It will be understood that the embodiments of 'the' invention illustrated in Figs. 2 and 3 of the drawing are useful in the type of discharge device illustrated in Fig. 1.

The discharge device shown in Fig. 1 has a bulb I to which a stem tube 2 has been scaled. This stem tube 2 carries a glass stem 3 to which two metal supporting wires 4 are fastened. Two sup porting wires 5 and 6 are sealed into the stem tube 2. Between these supporting wires 5 and 6 and the ends of the supporting wires 4, two resistance wires 1 and 8, which consist of tungsten, for example, are fastened, while between the two of the discharge path the ends of the supporting when desired. The heating element of this type I cathode 9 consists of a nickel filament wrapped around a tungsten filament and a coating of material of high electron emissivity characteristics, for'example, barium oxide. The resistances I and 8 and the cathode 9 are connected in series, while the supporting wires 5 and 8 constitute the continuation of the resistances I and 8 but are considerably stronger than the latter. The supporting wires 5 and 6 are connected to the current-supply wires l8 and II.

The discharge device has a gas filling therein, consisting of a mixture of a rare, starting gas, such as neon at a few mm. pressure, and a metal vapor, such as mercury vapor.

When the discharge device is connected to an alternating current source, the current flowing through the resistances I and 8 and the cathode 9 produces a potential difference between the supporting wires 5 and 6 and the cathode 9. In the case of a sufficient electron emission by the cathode, a discharge takes place during every alternating-current half cycle between the cathode 9 and the supporting wire which has a positive potential with respect to the cathode 9. The discharge takes place, for instance, between the supporting wire 5 and the cathode 9. The discharge current flows then through the resistance 8 which serves as the stabilizing resistance for the discharge. ,In the next half cycle the discharge takes place between the glow cathode 9 and the supporting wire 6, while the resistance I in that case serves as the series resistance. The resistances I and 8 are of such size that they become incandescent during the operation of the device and emit light. This light is mixed with the light produced by the discharge.

In order to take the resistances i and 8 out wires 4 are bent to the rear so that the resistances 1 and 8 do not lie in the plane of the supporting wires 5 and 6.

' The'cathode 8 is of the indirectly heated type,

of cathode is connected to the supporting wires 4. The heating element of the cathode is surrounded by a small metal cylinder which is covered with a substance of high electron emissivity characteristics, such as barium oxide, and which is electrically connected to a point on the heating element. This embodiment is shown in Fig. 2 of the drawing in which 12 indicates the indirectly heated cathode.

In the constructions according to Figs. 1 and 2', the resistances I and 8 serve both for the production of the necessary voltage difierence for the discharge and also for limiting the discharge current. If the requirements which are placed on the resistances by this double function, cannot be made to agree, the arrangement shown schematically in Fig. 3 is used. In this case two thermionic cathodes l3 and I 4 similar to the cathode 9 of Fig. 1, and a resistance l5 connected between these cathodes l3,and H, are connected in series with, and placed between the resistances 1 and 8. The discharge takes place between the cathode l3 and the supporting wires 6, while the resistance 1 serves as the series impedance, or the .supporting wires 4 a cathode 9 is mounted. Said discharge takes place between the cathode l4 and the supporting wire 5, in which case the resistance. 8 functions as the series resistance. The voltage difference between the cathode l3 and the wire 8 or between'the cathode H and the wire 5 is brought about by the resistances 8 and I5 connected'in series and thecathode' I4, or by the resistances and I5 and the cathode I 8. The resistance l5 consequently coacts in the production of the discharge voltage but does not contribute to the limitation of the discharge current; this is accomplished by the resistances 1 and 8. The

resistances I and '8 in this embodiment are dimensioned in such a way that they eflfect a good stabilization while independently thereof the magnitude of the resistance I5 is selected in such a way that a voltage difference favorable for the discharge is produced thereby.

While have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:-

. 1. A gaseous electric discharge device comprising a container, a gaseous atmosphere therein, two resistances, a current lead for each of said resistances and a thermionic cathode sealed therein, said resistances being connected in series across said current leads and said cathode being connected in series with said resistances, said cathode being mounted between said resistances said current leads serving as anodes for said cathode.

2. A gaseous electric discharge device comprising a container, a gaseous atmosphere therein, two resistances, a current lead for each of said resistances and a thermionic cathode sealed therein, said resistances being connected in series across said current leads and said cathode being connected in series with said resistances, said cathode being mounted between said resistances, said current leads serving as anodes for said cathode, said resistances being heated to incandescence by the operating current of said device.

sistances and said cathodes being connected in series, each of said cathodes being mounted between a pair of said resistances, said current leads serving as anodes for said cathodes, said resistances being heated to incandescence by the operating current of said device.

EDUARD G. DQRGELO. 

